1. Field of the Invention
Embodiments of the present invention relate to a light-emitting device including a light-emitting element.
2. Description of the Related Art
Light-emitting devices using semiconductor light-emitting elements have a compact size and good power efficiency. Therefore, light-emitting devices including semiconductor light-emitting elements such as light-emitting diodes (LEDs) or laser diodes (hereinafter, referred to as “LD(s)”) are employed for various types of light sources. Here, light produced by a semiconductor light-emitting element has a steep spectral distribution. Accordingly, for a light-emitting device producing white color light, it is necessary to convert the wavelengths of light produced by the semiconductor light-emitting elements.
For a method for producing white color light, there are three main known methods described below. First, there is a first light-emitting device combining a blue color LED and a YAG phosphor emitting yellow color light. In the first light-emitting device, the YAG phosphor is excited by light from the blue color LED to produce white color light formed by a light mixture of blue color light and yellow color light. In a second light-emitting device combining an ultraviolet LED and phosphors, three types of phosphors, which emit blue, green and red color light, respectively, are used for the phosphors. The second light-emitting device produces white color light using a light mixture of the blue, green and red color light from the phosphors. There is also a third light-emitting device of what is called a three band mixture type including a combination of a blue color LED, a green color LED and a red color LED.
For example, Japanese Patent Application Laid-Open Publication No. 2005-93896 discloses a variation of the first light-emitting device combining a blue color LED and two types of phosphors. As illustrated in FIG. 1, a light-emitting device 101, in which a mortar-shaped recess portion is provided in a base material 130 and an LED chip 104 is disposed on a bottom surface 103 of the recess portion, includes a first wavelength conversion member 105 prepared by dispersing a first phosphor, which produces green color fluorescence, in a light transmissive resin, a second wavelength conversion member 106 prepared by dispersing a second phosphor, which produces red color fluorescence, in a light transmissive resin, and a reflective surface 102 formed on an inner surface of the recess portion.